Science and technology

Influence of grinding direction on fracture strength of silicon nitride

Article Abstract:

Analysis of surface grinding of reaction-bonded and sintered reaction-bonded silicon nitride flexure bars shows that flaws produced in fracture strength are directional in nature. Under the same grinding conditions, transverse grinding shows greater reduction in the fracture strength of samples as compared to longitudinal grinding. Increasing the material removal rate reduces the fracture strength during transverse grinding. However, the fracture strength is unaffected by varying the material removal rates during longitudinal grinding.

Author: Strakna, T.J., Jahanmir, S., Allor, R.L., Kumar, K.V.

Publisher:American Society of Mechanical EngineersPublication Name:Journal of Engineering Materials and TechnologySubject:Science and technologyISSN:0094-4289Year:1996

The thermoelastic effect of material anisotropy and curing stresses on interlaminar embedded elliptical delamination fracture characteristics in multiply laminated fiber-reinforced polymeric (FRP) composites are studied. It is found that the individual modes of energy release rates vary along the delamination front depending on the ply sequence, orientation and thermoelastic material anisotropy of the constituting laminae, which causes the anisotropic, and non-self similar delamination propagation along the interface.

Author: Pradhan, Brajabandhu, Panda, Saroja Kanta

Publisher:American Society of Mechanical EngineersPublication Name:Journal of Engineering Materials and TechnologySubject:Science and technologyISSN:0094-4289Year:2006

Stable crack growth in rate-dependent materials with damage

Article Abstract:

Crack growth under small-scale-creep/damage conditions is investigated by a cohesive zone model of the Dugdale-Barenblatt type. The power law viscous overstress relation, which is modified by a damage function of the Kachanov type, describes the material inside the cohesive zone. The investigation of the velocity dependence of the fracture toughness shows that it is directly proportional to the velocity, and that it asymptotically approaches the instance that neglects damage.

Author: Fager, Leif-Olof, Bassani, J.L.

Publisher:American Society of Mechanical EngineersPublication Name:Journal of Engineering Materials and TechnologySubject:Science and technologyISSN:0094-4289Year:1993